Fix Add-AzKeyVaultKey doc (keyops)

[isra-fel]

Description

(The original PR #10955 by @felickz contains too many conflicts so I cherry-picked the commit here)

As per https://tools.ietf.org/html/draft-ietf-jose-json-web-key-41

"wrapKey" (encrypt key)
"unwrapKey" (decrypt key and validate decryption, if applicable)
These values are required as inputs to the KeyOps parameter
ex: "key_ops":["wrapKey","unwrapKey"]

Using the value "wrap" and "unwrap" is not correct.

Besides after testing I found that -KeyOps only accepts lowercase like "encrypt". Passing "Encrypt" would result in a 400.
I also added "import" as a valid key op.

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
  • the markdown help files have been regenerated using the commands listed here

[adxsdkps]

Can one of the admins verify this patch?